When Valentina Fedi arrived at work last week, it struck her as unusually efficient that 20 beer kegs left outside the pub the night before had already been picked up.

Normally a driver wouldn't turn up at Goldy's, found on a quiet street corner in the inner Melbourne suburb of Collingwood, until later in the day.

Calls started coming in from other pubs. Their kegs were gone too. 

CCTV footage was checked. At 6am — well after the pub had closed but well before it reopened — an unknown woman wearing high-vis and gloves could be seen methodically removing the kegs.

If it was a shock to the staff at Goldy's, it had been more of a slow-burn realisation for David Ong.

The co-owner of 2 Brothers Brewery, which supplies venues across Melbourne with kegs of beer and cider, was going through his inventory last week after a busy Christmas period when he noticed something was off.

Since the back-end of last year, more than 300 kegs had gone missing from the independent business he started with his brother.

"I felt a bit foolish not keeping on top of our keg logs in November and December," he said.

"We were flat out. I guess I just took my eyes off things."

Victoria Police this week said they were investigating the theft of about $30,000 worth of kegs from pubs, bars and breweries across Melbourne in the past few months.

The true cost is far greater. David Ong believes 2 Brothers Brewery alone has lost more than $60,000 in stolen kegs.

It is an issue keg supplier Konvoy has been tracking, quite literally.

"Keg theft has always been there in in small numbers," Konvoy's general manager Nick Beckett said.

"There's always a barbecue or a fire pit that's been made [out of them] in the past, but we're talking bigger numbers now, we're talking something more organised.

Theft confounds industry

Empty beer kegs weigh a little over 12 kilograms and cost about $150-200 each, depending on how many you purchase at a time.

Most pubs leave their empty kegs out overnight for their suppliers to pick up. The kegs, which have a 30-year life span, then get taken away, cleaned, refilled, and are later returned, full of beer.

Their value as scrap metal represents a fraction of their value brand new — less than $20 a keg  — and that's only if you can find a scrap metal yard willing to turn a blind eye.

The ABC spoke to scrap metal yards which said they would refuse any kegs that didn't have a clear trail of ownership, but suggested there were others in the industry that might not be so scrupulous.

Konvoy's kegs have small tracking devices embedded in them.

In recent months, they have pinged in locations they shouldn't — like a northern suburbs industrial area, or a regional Victorian scrap yard.

There have also been instances where the tracking beacons have been knowingly removed from stolen kegs.

In other cases, like when around 200 kegs were stolen in one night from Canberra's Capital Brewing Co in December, 40 Konvoy-branded kegs were initially moved, then ultimately left behind.

Kegs from other brands without tracking devices were taken instead.

With no clear leads, it has led Nick Beckett to speculate whether some of those involved have experience within the industry.

"There's an elaborate supply chain network of people that deal with kegs, so I wouldn't be surprised if it was someone that's been in one of those roles at some stage," Mr Beckett said.

The ABC has been told Victoria Police visited a scrap metal yard on Friday morning and found loads of crushed kegs and dozens more waiting to be scrapped. 

A police spokesperson refused to comment but said investigations were ongoing.

Brewer says he's lost $100k

At independent brewer Hawkers, housed in the Melbourne suburb of Reservoir, Mazen Hajjar estimates his recent losses from keg theft are approaching $100,000. 

CCTV footage from his brewery late last year shows two men taking dozens of kegs from a stack kept inside his premises.

Many more of his kegs have been taken from outside bars and pubs.

"It's insane. It's absolutely insane," Mr Hajjar said.

Late last year, Mr Hajjar said a man came to the brewery offering to sell a host of discounted kegs — including some displaying Hawkers's branding.

He wasn't present at the time, and the contact details his staff took from the man turned out to be fake.

Konvoy believes the issue is creating a national keg shortage that's now impacting independent brewers.

"It's affecting our ability to sell beer," Mr Hajjar said.

Losses becoming 'catastrophic'

The sight of empty kegs piled outside pubs and small bars, unsecured and awaiting pick-up, is common across Australia. 

It might seem like an archaic way for an industry to operate, but it's borne out of pragmatic reality.

Few hospitality venues have the space to store kegs for extended periods of time, and fewer still have the staff available to coordinate with couriers making pick-ups from dozens of venues at a time.

At the Great Northern Hotel in Carlton, a sprawling old pub where 60 kegs were stolen last week, kegs are now kept in a cellar until the moment they are picked up.

Staff describe the enforced change as a "pain in the arse", but it's not an option for most venues.

Sitting in the front bar, David Ong from 2 Brothers Brewery is aware those in the alcohol industry may not attract the same level of empathy as other small businesses, but they are hurting nonetheless. 

"Most of the 600-odd breweries that exist in Australia are small businesses. A lot of them are family businesses or mates that have gotten together," Mr Ong said.

"It's like if you have a café and someone is coming inside and taking your fixtures and your assets.

"Losses like this, they really are catastrophic."